Patent GB-788352-A (GB)
Title: Improvements in and relating to electric signal storage devices and apparatus
Inventor: SIMPSON ANTHONY WILLIAM
IPC: H03K21/00
Filed: 1954-07-26
Abstract: 788,352. Electric digital-data-storage apparatus. PLESSEY CO., Ltd. July 11, 1955 [July 26, 1954], No. 21746/54. Class 106 (1). [Also in Groups XXXV and XXXIX] When current in a single conductor is passed through the aperture of a toroidal core formed of material having a substantially rectangular hysteresis loop to reverse the state of remanent magnetization, the value of current required depends on the aperture diameter. This principle is applied to storage of digital information in a group of ferrite toroids which have graded apertures, each of a different diameter, threaded by a common conductor to which a saw-toothed waveform is applied. As the current increases the initial magnetizations of the graded cores are reversed in turn, the number of cores affected being determined by the maximum value of the current. The group of cores may be constituted by holes 11, Fig. 2, of different diameters in a ferrite sheet 10, magnetic isolation between cores being effected by equally-spaced perforations around each hole as described in Specification 788,351, [Group XXXV]. Two silver printed conductors 12, 13, one an input winding and the other an output winding, pass through all the holes 11. Alternatively the group of cores may be formed from a series of ferrite sheets having holes of different diameters, the sheets being assembled as a stack with interleaved sheets of non-magnetic material and with the holes in alignment to permit the use of straight input and output conductors. A storage system for digits represented by pulse trains is shown in Fig. 3, each digit being registered on a separate group of graded cores 14 selected by a switch 17. A train of pulses is first applied over an amplifier and decimal counting tube circuit 19 to a dekatron 20, and causes the discharge between the anode and zero cathode 20a to be transferred to the cathode corresponding to the digital value of the pulses received. When a " read-in " sawtoothed voltage 21 reaches a zero value, a timing unit (not shown) opens a, gate 22 and the " readin " voltage is applied over a drive unit 23 to a common input conductor 15 of a core group 14. As all the cores are initially magnetized in the same sense, the "read-in" voltage causes reversal of magnetism to occur in turn. On each flux reversal of a core, a pulse is established in a common " read-out " conductor 16 which acts over circuit 19 to move the discharge in the dekatron 20 back towards the zero cathode. When this stage is reached, the number of core flux reversals equals the number of pulses received at terminal 18, and the voltage developed across resistor 25 closes gate 22. To read out the stored information, the core group is connected by a switch 24 to an output terminal 26 and a gate 27 is opened. A sawtoothed voltage 28 of opposite polarity 21 is applied to conductor 15, and those cores having reversed fluxes are restored in turn to their initial condition. As a result, a train of induced pulses equal in number to the stored digit is produced at terminal 26.